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Executive summary

The goal of this proposal is to offer a pragmatic view of a global climate deal that:

  1. countries might realistically agree to,
  2. countries might be able to actually achieve, and
  3. would achieve substantial reductions in greenhouse gas emissions.

A reasonable goal at this point in time is to stabilize CO2 concentrations around 600-650 ppm. Given the the current CO2 concentrations (~390 ppm) and the political challenges reaching a deal, an extremely ambitious goal of 350 or 450 is simply not realistic.  The most important thing is that the global community agrees to take some type of action now. Setting a goal of around 650 ppm entails national policies that countries might actually be willing to agree to and, most importantly, is still aggressive enough to avoid/significantly reduce the worst risks of climate change.  Most of the effort of our plan is supported by developed countries, but developing countries are still required to reduce their emissions relative to BAU.  

Some might disagree with the assertion that a 650 ppm target avoids the worst risks of climate change, but a sensible discussion of the subject must conclude that stabilization near 650 ppm certainly poses less climate risk than a BAU scenario (~1000 ppm).  Given the lack of international action so far, and the risk of paralysis and continued inaction in the face of an unrealistically stringent target, it is our view that setting a moderate target poses less total risk than a more aggressive target.        



We are all students at MIT working at the Joint Program for Science and Policy of Global Change on the field of assessment and adaptation to global change. We have very different backgrounds, from atmospheric sciences to economics or policy.

  • Timothy Cronin is a PhD candidate in Earth, Atmospheric, and Planetary Sciences. He is working on land-atmosphere interactions under climate change.
  • Arthur Gueneau is a master candidate in technology and policy. He is working on assessing the impact of climate change on agriculture.
  • Jennifer Morris is a PhD candidate in the Engineering Systems division. She is working on building a renewable energy portfolio under a cap-and-trade policy.
  • Paul Kishimoto is a master candidate in technology and policy. He is working on designing a smart electrical grid.


What: Actions and impacts


Developed countries begin the policy in 2012 and are required to make reductions relative to 2005 by 2050. Rapidly developing countries do not face policy constraints until 2020 at which point they must limit the growth of their emissions such that by 2050 emissions levels are no more than 100% above 2005 levels. Although emissions are allowed to increase from 2005 levels, this policy still represents significant emissions reductions relative to business as usual (BAU). Similarly, other developing do not face policy until 2030 at which point they must limit the growth of their emissions such that by 2100 emissions levels are no more than 50-200% above 2005 levels, depending on the country. Fairness is key to an internationally acceptable agreement. Targets are as follows:

Developed Countries:Start Year 2012, Target Year 2050

USA: reduce emissions by 25% below 2005 levels by 2050

EU: reduce emissions by 30% below 2005 levels by 2050

Russia/FSU: reduce emissions by 10% below 2005 levels by 2050

OECD Asia: reduce emissions by 15% below 2005 levels by 2050

Canada: reduce emissions by 30% below 2005 levels by 2050


Rapidly Developing Countries:Start Year 2020, Target Year 2050

China, India, Brazil, South Africa, Mexico, and Rapidly Developing Asia: by 2050 emissions can be no more than 100% above 2005


Other Developing Countries:Start Year 2030, Target Year 2100 

Middle East: by 2100 emissions can be no more than 50% above 2005

Latin America: by 2100 emissions can be no more than 100% above 2005

Africa: by 2100 emissions can be no more than 200% above 2005


Land Use:

Emissions from deforestation: 0.5, deforestation emissions are reduced by 45% by 2050

Sequestration due to tree growth: 0.5, 0.8 billion tons of carbon removed per year


Developing Country Assistance: 

A fund of $150 billion per year shall be established to assist developing countries in reducing emissions and switching to cleaner energy forms. developed countries shall contribute to this fund in proportion to the amount of emissions they release each year.

Financial assistance to developing countries is an essential component of any global climate agreement. Although developing countries were demanding $500 billion per year at Copenhagen, the actions in this plan are not as drastic as those discussed then and so should not require as much assistance. Also developed countries are more likely to agree to a more reasonable amount of $150 billion.


Anticipated Impacts

These actions are anticipated to result in a CO2 concentrations a bit over 600 ppm and a temperature increase of about 3 degrees C above preindustrial by 2100. Mitigation costs are expected to be -4.1% to 0% (change in GDP in 2100) and damage costs are expected to be -4.1% to 0.4% (change in GDP in 2100). Sea level is expected to rise by roughly 80 cm.  These significant negative impacts are based on both the IPCC and Tyndall Center projections for the end of the century; damages are much smaller if we limit our time frame to 2050.  

It is important to note that the climate and carbon cycle models used to derive these figures are both deterministic, and give no sense of these substantial uncertainties inherent in climate policy decisions.  Real policy must adapt to the realities of the climate system; higher-than-expected climate sensitivity and/or natural emissions will require more significant action by all parties than we have outlined here.  It is our view that future decisions to decrease the stabilization target will be much easier if all major parties have already begun to take action, and that trying to assign too much certainty to the behavior of the earth system (human and natural) 50 years in the future is counterproductive.       

Why: Rationale for the proposal

The rationale for this proposal was to put something together that might actually have a chance of passing so as to start doing something on climate ASAP. Although ~650 ppm might not be an ideal CO2 concentration goal, it will suffice as a starting goal. We have seen that countries are unwilling/unable to commit to policies that aim to achieve 500 ppm or less. The actions required to meet ~650, on the other hand are manageable and may be able to get countries on board. We believe that getting some kind of agreement started now is of utmost importance. We cannot afford to keeping pushing for idealized policies (like 450 ppm or the extremely naive 350 ppm) which continually fail to produce agreements. It is time to be pragmatic and do the best we can. We believe this policy is something that countries might actually agree to, something that countries might realistically be able to achieve, and most importantly something that would still make a significant contribution to fighting climate change. A policy that achieves 650 ppm is still aggressive enough to avoid/significantly reduce the worst risks of climate change, and we need to start hedging those risks. If in the future, the need for a more stringent target is widely recognized, it will be much easier to accomplish if all major parties have already begun to take action.

Rationale for the targets:

  • The EU and Canada have already begun reducing their emissions making it easier for them to meet the stated targets. Russia and FSU have had a huge decrease in their emissions due to the economic collapse following the end of Soviet Union; considering that their economy is quickly recovering we expect these countries to have more difficulty reducing their emissions. The USA has been extremely reluctant to enact efficient policies against climate change; hence the slightly more modest target as compared to other developed countries.  However an international consensus cannot be reached without participation of the United States, and the dynamism of the country's economy make it likely to reach high standards once global change problems are addressed.
  • We think that rapidly developing countries need a decade to adapt their recent economic growth to the challenges of climate change so the start year for their policies is 2020. As their emissions grow in a BAU scenario until 2020, we think that a doubling of their emissions by 2050 relative to 2005 is a reasonable target for now.
  • When considering other developing countries (except oil-rich Middle East) we consider that no international policy should prevent them from reasonable economic development that will elevate their populations out of poverty and starvation.  We have thus chosen for them a starting year of 2030, and we think that they should have the right to double or triple their emissions relative to 2005 levels.
  • We consider middle-of-the road deforestation and afforestation/sequestration rates because of the relative efficiency of the UN-REDD program compared to the deforestation needed to pursue economic growth in developing countries.


How: Feasibility of proposal

We see a portfolio of advanced technologies playing an important role in the future energy mix:

  • Natural Gas: natural gas will play an important role as a transition technology as it is much cleaner than goal and much cheaper than renewables and other advanced technologies. Natural Gas is particularly important in the US, Mexico, Canada, Russia, parts of Europe and parts of Asia, the Middle East, and Africa. 
  • Renewables (wind, solar, hydro etc.): we see an substantial role for renewable energy. Important increases in the US, Europe, China, and Canada. Also renewables provide important opportunities to increase electricity access in Africa and Latin America. Hydro is particularly significant in Brazil, Canada, Latin America, and parts of Asia and Europe.
  • Nuclear: we see an expanded role for nuclear power. Increases are expected in US, Japan, Europe, Russia, China, India and Asia
  • Carbon Capture and Storage: we anticipate the development of CCS technologies that will enable US, China, and Australia to make use of their coal resources in a clean way. We also think CCS for natural gas will be an important contributor particularly in the US, Mexico, Russia, Europe, Africa, the Middle East and Asia.
  • Clean transportation: biofuels are expected to increase, however because of their land use impacts and life-cycle emissions they will not be the replacement of oil we expected. As a result electric vehicles will play an important role in cleaning up the transportation sector.
  • Efficiency: efficiency opportunities will be capitalized upon extensively; new building construction materials and a smart energy grid are some of them

We expect policies to vary at the national level. However we expect the majority of developed countries to pursue their reductions through a cap-and-trade system. We also expect at least some of the cap-and-trade systems to eventually be linked (for example between the US and Europe). All countries will pursue efficiency standards, i.e. for appliances, buildings, vehicles, etc. to reduce emissions. Renewable mandates (renewable portfolio standards or feed-in tariffs) that force a certain amount of electricity to come from renewables will also be common.

As most of the research and development in clean technologies and efficiency is likely to be private under cap-and-trade we expect to see technology transfers between developed and developing countries and adaptation of green techs to different environments.

The REDD agreement on deforestation along with the recent Nagoya protocol on biodiversity will help prevent deforestation. However developed countries need to help developing countries prevent deforestation by helping them to develop more intensive agricultural practices. GMOs will likely be part of the process once health safety concerns and intellectual property rights issues (now allowing multinationals to hold farmers hostage) are solved. Agricultural investments (e.g. development of climate-adapted crops, better water conservation practices) will allow global yields to continue to increase, and is key to protecting against deforestation.


Vision of the future under this proposal

We will not take the risk of depicting a snapshot of the future here; far too much is uncertain. Below we sketch some of the main economic and policy shifts by 2050, that are consistent with our policy objectives.

Scientific research will have improved our estimates of climate system response, and irreducible uncertainties may still remain, but the reality of anthropogenic climate change will no longer be a hotly disputed issue. Rising temperatures and sea levels will be obvious to the vast majority of policymakers; impacts such as spatially heterogeneous changes in crop yields and water availability will be evident to most.  However, the effects of the policies we have outlined will also be obvious: Green technologies will be prevalent everywhere, and environmental efficiency will be the new standard for construction and manufacturing. Green technologies may be the next large frontier of economic growth in the 2020s and 2030s.  Continued innovation and diffusion of information technologies will enable a global population of roughly 9 billion to cooperate to face the climate stabilization challenge.

With the emergence of China, Brazil and India as new superpowers the world will have become multipolar. As these countries will be facing more intense effects of climate change than older powers, climate mitigation will be at the heart of diplomatic agenda. Even if some environment-related wars may arise (due to water and land shortage) they are not likely to happen between powerful countries. A more ambitious climate agreement is likely to happen mid-century thanks to better technologies and to a better understanding of climate system mechanisms.